Characterization of plant growth-promoting rhizobacterial isolates associated with food plants in South Africa

Abstract

The region around the plant root referred to as the rhizosphere, is the zone where various microbial activity occurs. It performs crucial functions such as increasing the uptake of nutrients for plant development and preventing plant against plant pathogens. Keeping in mind the beneficial role performed by rhizospheric microorganisms, rhizobacterial species were isolated from the maize and soybean plant's rhizosphere. The isolated microorganisms were evaluated for their biochemical characteristics, plant growth-promoting potentials, tolerance to different environmental conditions, and their antifungal activity against Fusarium graminearum, a fungal pathogen that infects maize. The rhizobacterial isolates with multiple plant growth-promoting potentials were identified as Bacillus spp (80.77%), Rhodocyclaceae bacterium (3.85%), Enterococcus spp (3.85%). Massilia spp (3.85%. and Pseudomonas (7.69%) species based on their 16S rRNA molecular characterization. The bacterial isolates possessed antifungal activities against Fusarium graminearum, promote maize and soybeans seed under laboratory conditions, and exhibited different levels of tolerance to pH, temperature, salt, and heavy metal. Based on this, the whole genome sequencing of Bacillus sp. OA1, Pseudomonas rhizosphaerea OA2, and Pseudomonas sp. OA3 was performed using Miseq Illumina system to determine the functional genes and secondary metabolites responsible for their plant growth-promoting potential Thus, the result of this research revealed that the selected bacterial isolates possess plant growth-promoting potentials that can make them a potential candidate to be employed as microbial inoculants for protecting plants against phytopathogens, environmental stress and increasing plant growth and productivity.

Isolation and Characterization of Plant-Growth-Promoting, Drought-Tolerant Rhizobacteria for Improved Maize Productivity

“…The rhizobacteria strains, A1-2 and C7_8, exhibited varied drought tolerance at varied salinity, pH, temperature, and heavy metal stress, which stimulated plant growth when they co-existed to ameliorate effects of the stressors and corroborated the findings of Abedinzadeh et al [68], who affirmed the potential effects of abiotic stressors on plant growth, through enzyme and protein synthesis. The results from this study are similar to the findings of Fasusi et al [69], who affirmed the plant-growth-promoting tendencies of PGPR isolated from food plants in South Africa.…”

Synergistic effects of substrate inoculation with Pseudomonas strains on tomato phenology, yield, and selected human health‐related phytochemical compounds

“…In this study, bacterial isolates could withstand circumstances that hinder plant growth. Establishing efficacy is crucial, and the results confirm previous findings (Fasusi et al., 2021; Gashaw et al., 2022; Getahun et al., 2020; Ghadamgahi et al., 2022; Yaghoubi Khanghahi et al., 2021).…”

Identification and in vitro Characterization of Plant Growth-promoting Pseudomonas spp. Isolated from the Rhizosphere of Tomato (Lycopersicum esculentum) Plants in Kenya

“…The bacterial isolates examined in this study could resist environmental conditions that could impair plant growth. It is critical for determining the efficacy of the bacterial isolate, and the result obtained confirms prior findings [23,[49][50][51][52].…”